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<h1 class="title">dragwidget.cpp 示例文件</h1>
<span class="subtitle">draganddrop/draggabletext/dragwidget.cpp</span>
<!-- $$$draganddrop/draggabletext/dragwidget.cpp-description -->
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<pre class="cpp">

  <span class="comment">/****************************************************************************
  **
  ** Copyright (C) 2016 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the examples of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:BSD$
  ** Commercial License Usage
  ** Licensees holding valid commercial Qt licenses may use this file in
  ** accordance with the commercial license agreement provided with the
  ** Software or, alternatively, in accordance with the terms contained in
  ** a written agreement between you and The Qt Company. For licensing terms
  ** and conditions see https://www.qt.io/terms-conditions. For further
  ** information use the contact form at https://www.qt.io/contact-us.
  **
  ** BSD License Usage
  ** Alternatively, you may use this file under the terms of the BSD license
  ** as follows:
  **
  ** &quot;Redistribution and use in source and binary forms, with or without
  ** modification, are permitted provided that the following conditions are
  ** met:
  **   * Redistributions of source code must retain the above copyright
  **     notice, this list of conditions and the following disclaimer.
  **   * Redistributions in binary form must reproduce the above copyright
  **     notice, this list of conditions and the following disclaimer in
  **     the documentation and/or other materials provided with the
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  **     from this software without specific prior written permission.
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  ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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  ** $QT_END_LICENSE$
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  ****************************************************************************/</span>

  <span class="preprocessor">#include &lt;QtWidgets&gt;</span>

  <span class="preprocessor">#include &quot;dragwidget.h&quot;</span>

  <span class="keyword">static</span> <span class="type"><a href="qlabel.html">QLabel</a></span> <span class="operator">*</span>createDragLabel(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span> <span class="operator">&amp;</span>text<span class="operator">,</span> <span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span>parent)
  {
      <span class="type"><a href="qlabel.html">QLabel</a></span> <span class="operator">*</span>label <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qlabel.html">QLabel</a></span>(text<span class="operator">,</span> parent);
      label<span class="operator">-</span><span class="operator">&gt;</span>setAutoFillBackground(<span class="keyword">true</span>);
      label<span class="operator">-</span><span class="operator">&gt;</span>setFrameShape(<span class="type"><a href="qframe.html">QFrame</a></span><span class="operator">::</span>Panel);
      label<span class="operator">-</span><span class="operator">&gt;</span>setFrameShadow(<span class="type"><a href="qframe.html">QFrame</a></span><span class="operator">::</span>Raised);
      <span class="keyword">return</span> label;
  }

  <span class="keyword">static</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span> hotSpotMimeDataKey() { <span class="keyword">return</span> <span class="type"><a href="../qtcore/qstring.html#QStringLiteral">QStringLiteral</a></span>(<span class="string">&quot;application/x-hotspot&quot;</span>); }

  DragWidget<span class="operator">::</span>DragWidget(<span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span>parent)
      : <span class="type"><a href="qwidget.html">QWidget</a></span>(parent)
  {
      <span class="type"><a href="../qtcore/qfile.html">QFile</a></span> dictionaryFile(<span class="type"><a href="../qtcore/qstring.html#QStringLiteral">QStringLiteral</a></span>(<span class="string">&quot;:/dictionary/words.txt&quot;</span>));
      dictionaryFile<span class="operator">.</span>open(<span class="type"><a href="../qtcore/qiodevice.html">QIODevice</a></span><span class="operator">::</span>ReadOnly);
      <span class="type"><a href="../qtcore/qtextstream.html">QTextStream</a></span> inputStream(<span class="operator">&amp;</span>dictionaryFile);

      <span class="type">int</span> x <span class="operator">=</span> <span class="number">5</span>;
      <span class="type">int</span> y <span class="operator">=</span> <span class="number">5</span>;

      <span class="keyword">while</span> (<span class="operator">!</span>inputStream<span class="operator">.</span>atEnd()) {
          <span class="type"><a href="../qtcore/qstring.html">QString</a></span> word;
          inputStream <span class="operator">&gt;</span><span class="operator">&gt;</span> word;
          <span class="keyword">if</span> (<span class="operator">!</span>word<span class="operator">.</span>isEmpty()) {
              <span class="type"><a href="qlabel.html">QLabel</a></span> <span class="operator">*</span>wordLabel <span class="operator">=</span> createDragLabel(word<span class="operator">,</span> <span class="keyword">this</span>);
              wordLabel<span class="operator">-</span><span class="operator">&gt;</span>move(x<span class="operator">,</span> y);
              wordLabel<span class="operator">-</span><span class="operator">&gt;</span>show();
              wordLabel<span class="operator">-</span><span class="operator">&gt;</span>setAttribute(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>WA_DeleteOnClose);
              x <span class="operator">+</span><span class="operator">=</span> wordLabel<span class="operator">-</span><span class="operator">&gt;</span>width() <span class="operator">+</span> <span class="number">2</span>;
              <span class="keyword">if</span> (x <span class="operator">&gt;</span><span class="operator">=</span> <span class="number">245</span>) {
                  x <span class="operator">=</span> <span class="number">5</span>;
                  y <span class="operator">+</span><span class="operator">=</span> wordLabel<span class="operator">-</span><span class="operator">&gt;</span>height() <span class="operator">+</span> <span class="number">2</span>;
              }
          }
      }

      setAcceptDrops(<span class="keyword">true</span>);
      setMinimumSize(<span class="number">400</span><span class="operator">,</span> <a href="../qtcore/qtglobal.html#qMax">qMax</a>(<span class="number">200</span><span class="operator">,</span> y));
      setWindowTitle(tr(<span class="string">&quot;Draggable Text&quot;</span>));
  }

  <span class="type">void</span> DragWidget<span class="operator">::</span>dragEnterEvent(<span class="type"><a href="../qtgui/qdragenterevent.html">QDragEnterEvent</a></span> <span class="operator">*</span>event)
  {
      <span class="keyword">if</span> (event<span class="operator">-</span><span class="operator">&gt;</span>mimeData()<span class="operator">-</span><span class="operator">&gt;</span>hasText()) {
          <span class="keyword">if</span> (event<span class="operator">-</span><span class="operator">&gt;</span>source() <span class="operator">=</span><span class="operator">=</span> <span class="keyword">this</span>) {
              event<span class="operator">-</span><span class="operator">&gt;</span>setDropAction(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>MoveAction);
              event<span class="operator">-</span><span class="operator">&gt;</span>accept();
          } <span class="keyword">else</span> {
              event<span class="operator">-</span><span class="operator">&gt;</span>acceptProposedAction();
          }
      } <span class="keyword">else</span> {
          event<span class="operator">-</span><span class="operator">&gt;</span>ignore();
      }
  }

  <span class="type">void</span> DragWidget<span class="operator">::</span>dropEvent(<span class="type"><a href="../qtgui/qdropevent.html">QDropEvent</a></span> <span class="operator">*</span>event)
  {
      <span class="keyword">if</span> (event<span class="operator">-</span><span class="operator">&gt;</span>mimeData()<span class="operator">-</span><span class="operator">&gt;</span>hasText()) {
          <span class="keyword">const</span> <span class="type"><a href="../qtcore/qmimedata.html">QMimeData</a></span> <span class="operator">*</span>mime <span class="operator">=</span> event<span class="operator">-</span><span class="operator">&gt;</span>mimeData();
          <span class="type"><a href="../qtcore/qstringlist.html">QStringList</a></span> pieces <span class="operator">=</span> mime<span class="operator">-</span><span class="operator">&gt;</span>text()<span class="operator">.</span>split(<span class="type"><a href="../qtcore/qregularexpression.html">QRegularExpression</a></span>(<span class="type"><a href="../qtcore/qstring.html#QStringLiteral">QStringLiteral</a></span>(<span class="string">&quot;\\s+&quot;</span>))<span class="operator">,</span>
                               <span class="type"><a href="../qtcore/qstring.html">QString</a></span><span class="operator">::</span>SkipEmptyParts);
          <span class="type"><a href="../qtcore/qpoint.html">QPoint</a></span> position <span class="operator">=</span> event<span class="operator">-</span><span class="operator">&gt;</span>pos();
          <span class="type"><a href="../qtcore/qpoint.html">QPoint</a></span> hotSpot;

          <span class="type"><a href="../qtcore/qbytearraylist.html">QByteArrayList</a></span> hotSpotPos <span class="operator">=</span> mime<span class="operator">-</span><span class="operator">&gt;</span>data(hotSpotMimeDataKey())<span class="operator">.</span>split(<span class="char">' '</span>);
          <span class="keyword">if</span> (hotSpotPos<span class="operator">.</span>size() <span class="operator">=</span><span class="operator">=</span> <span class="number">2</span>) {
              hotSpot<span class="operator">.</span>setX(hotSpotPos<span class="operator">.</span>first()<span class="operator">.</span>toInt());
              hotSpot<span class="operator">.</span>setY(hotSpotPos<span class="operator">.</span>last()<span class="operator">.</span>toInt());
          }

          <span class="keyword">for</span> (<span class="keyword">const</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span> <span class="operator">&amp;</span>piece : pieces) {
              <span class="type"><a href="qlabel.html">QLabel</a></span> <span class="operator">*</span>newLabel <span class="operator">=</span> createDragLabel(piece<span class="operator">,</span> <span class="keyword">this</span>);
              newLabel<span class="operator">-</span><span class="operator">&gt;</span>move(position <span class="operator">-</span> hotSpot);
              newLabel<span class="operator">-</span><span class="operator">&gt;</span>show();
              newLabel<span class="operator">-</span><span class="operator">&gt;</span>setAttribute(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>WA_DeleteOnClose);

              position <span class="operator">+</span><span class="operator">=</span> <span class="type"><a href="../qtcore/qpoint.html">QPoint</a></span>(newLabel<span class="operator">-</span><span class="operator">&gt;</span>width()<span class="operator">,</span> <span class="number">0</span>);
          }

          <span class="keyword">if</span> (event<span class="operator">-</span><span class="operator">&gt;</span>source() <span class="operator">=</span><span class="operator">=</span> <span class="keyword">this</span>) {
              event<span class="operator">-</span><span class="operator">&gt;</span>setDropAction(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>MoveAction);
              event<span class="operator">-</span><span class="operator">&gt;</span>accept();
          } <span class="keyword">else</span> {
              event<span class="operator">-</span><span class="operator">&gt;</span>acceptProposedAction();
          }
      } <span class="keyword">else</span> {
          event<span class="operator">-</span><span class="operator">&gt;</span>ignore();
      }
      <span class="keyword">for</span> (<span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span>widget : findChildren<span class="operator">&lt;</span><span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span><span class="operator">&gt;</span>()) {
          <span class="keyword">if</span> (<span class="operator">!</span>widget<span class="operator">-</span><span class="operator">&gt;</span>isVisible())
              widget<span class="operator">-</span><span class="operator">&gt;</span>deleteLater();
      }
  }

  <span class="type">void</span> DragWidget<span class="operator">::</span>mousePressEvent(<span class="type"><a href="../qtgui/qmouseevent.html">QMouseEvent</a></span> <span class="operator">*</span>event)
  {
      <span class="type"><a href="qlabel.html">QLabel</a></span> <span class="operator">*</span>child <span class="operator">=</span> qobject_cast<span class="operator">&lt;</span><span class="type"><a href="qlabel.html">QLabel</a></span><span class="operator">*</span><span class="operator">&gt;</span>(childAt(event<span class="operator">-</span><span class="operator">&gt;</span>pos()));
      <span class="keyword">if</span> (<span class="operator">!</span>child)
          <span class="keyword">return</span>;

      <span class="type"><a href="../qtcore/qpoint.html">QPoint</a></span> hotSpot <span class="operator">=</span> event<span class="operator">-</span><span class="operator">&gt;</span>pos() <span class="operator">-</span> child<span class="operator">-</span><span class="operator">&gt;</span>pos();

      <span class="type"><a href="../qtcore/qmimedata.html">QMimeData</a></span> <span class="operator">*</span>mimeData <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="../qtcore/qmimedata.html">QMimeData</a></span>;
      mimeData<span class="operator">-</span><span class="operator">&gt;</span>setText(child<span class="operator">-</span><span class="operator">&gt;</span>text());
      mimeData<span class="operator">-</span><span class="operator">&gt;</span>setData(hotSpotMimeDataKey()<span class="operator">,</span>
                        <span class="type"><a href="../qtcore/qbytearray.html">QByteArray</a></span><span class="operator">::</span>number(hotSpot<span class="operator">.</span>x()) <span class="operator">+</span> <span class="char">' '</span> <span class="operator">+</span> <span class="type"><a href="../qtcore/qbytearray.html">QByteArray</a></span><span class="operator">::</span>number(hotSpot<span class="operator">.</span>y()));

      <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> dpr <span class="operator">=</span> window()<span class="operator">-</span><span class="operator">&gt;</span>windowHandle()<span class="operator">-</span><span class="operator">&gt;</span>devicePixelRatio();
      <span class="type"><a href="../qtgui/qpixmap.html">QPixmap</a></span> pixmap(child<span class="operator">-</span><span class="operator">&gt;</span>size() <span class="operator">*</span> dpr);
      pixmap<span class="operator">.</span>setDevicePixelRatio(dpr);
      child<span class="operator">-</span><span class="operator">&gt;</span>render(<span class="operator">&amp;</span>pixmap);

      <span class="type"><a href="../qtgui/qdrag.html">QDrag</a></span> <span class="operator">*</span>drag <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="../qtgui/qdrag.html">QDrag</a></span>(<span class="keyword">this</span>);
      drag<span class="operator">-</span><span class="operator">&gt;</span>setMimeData(mimeData);
      drag<span class="operator">-</span><span class="operator">&gt;</span>setPixmap(pixmap);
      drag<span class="operator">-</span><span class="operator">&gt;</span>setHotSpot(hotSpot);

      <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>DropAction dropAction <span class="operator">=</span> drag<span class="operator">-</span><span class="operator">&gt;</span>exec(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>CopyAction <span class="operator">|</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>MoveAction<span class="operator">,</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>CopyAction);

      <span class="keyword">if</span> (dropAction <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>MoveAction)
          child<span class="operator">-</span><span class="operator">&gt;</span>close();
  }

</pre>
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<!-- @@@draganddrop/draggabletext/dragwidget.cpp -->
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